[37.09] Cassini ISS Search for Inner Satellites of Jupiter

During Cassini's approach to Jupiter, from 4 Oct 2000 to 6
Dec 2000, a series of narrow angle images was taken to
search for any undiscovered satellites of Jupiter, focusing
(to avoid scattered light from Jupiter) on the region from
2.6 RJ to 20 RJ, exterior to Amalthea but interior to
Callisto. The spacecraft's distance to Jupiter for these
images ranged from 82 million km to 25 million km, and the
phase angle ranged from 20 degrees to 8 degrees. Due to
limitations on observing time on the spacecraft, image
sequences were taken at intervals ranging from many hours to
days. The movement of the spacecraft, as well as the
movement of any observed satellites, over these intervals
would be so large as to make it impossible to identify
objects by observing movement against a background of stars.
Instead, a correlation technique was applied, which
restricted the search to satellites with near-planar,
near-circular orbits. These assumptions place additional
limits on the orbital elements of any detectable satellite.
At present, we are confident that no satellites exist in the
search region with magnitudes (as seen from the spacecraft)
brighter than 14.5, inclinations below 1.5 degrees, and
eccentricities below 0.0002. This limit corresponds to an
object with a diameter of 15 km, with an albedo of 0.1, at a
range of 40 million km.